Emco PC Turn 55

[Threedj16]

OK, I found a diagram someone came up with for the PC Turn 55. Only issue is they have the power in two pins reversed. Wouldn't be a big deal if it wasn't for that polarized cap on the board....LOL.... . Other than that, this old board worked beautifully. Pulls about 100-120ma running forward and about 50-60ma locked in reverse.

Tried to upload the diagram but it's giving me an upload quota reached error.

Also finally got my supports built today for all the DIN rail mounts and wire ways going in the back of the cabinet. Might get around this weekend to installing them finally.

[Threedj16]

Well, finally starting to get things together. Decided to go with the Automation Direct Nema 23 Closed Loop Stepper setup for this Emco and not use the G540. Also got all my components tested out (turret board, optical switches and hall effect sensors). I can't believe after all these years, all of it worked perfectly. So the hall effects on the ball screw pulleys are NPN and normally closed. They operate at 24v. Someone was nice enough to leave a tag on one with the wire setup and information. The optical switches for the tool turret operates at 5v. They are both normally closed and tool switch opens when the tool position tab passes over it. The zero tool is held open (closer into center, so metal always covering it until zero) and closes when the zero position slot passes over it.

I've read through the forum a ton the last few weeks and have seen numerous ways people are connecting 5v to the 24v inputs on the Acorn. Using the closed loop steppers, I will also have two fault 5v signals too (which I'll tie to one input) in addition to the two 5v optical switches. My question is which would be better, just a simple 5v relay board to give the Acorn the 24v common or use opto isolator board? Not like any of this will be switching very fast. Just know a lot of you have done this and would love some opinions. I am doing everything DIN rail, the relays come on DIN mounts already. But I could easily 3D print a mount for the opto isolator board too. Appreciate the input in advance.

Relay board - https://www.amazon.com/Channels-5VDC-Re ... +board+din


Question number two. Anyone have a suggestion for mounting the encoder on the Emco PC turn 55? My thoughts are to remove the pulley and existing encoder cutout wheel, so I will have room for a timing pulley and belt behind the existing pulley. Though I have no idea where to find spline drive timing pulleys. Third questions, any suggestions on how to get that thing off? I pulled the snap ring off, even heated it....no luck. Pretty scared to use a gear puller on this tiny of a pulley (lot of meat on the hub, but little on the belt slots). So if anyone has pulled this off, please tell me the trick. Pic below of the pulley.

Anyway, thanks again for any input on this. Finally getting close to getting to the good part of my build, just a few more parts on the list to get.

[DICKEYBIRD]

Those splines look rusty; perhaps a soaking with PB Blaster or the like might help? I know you're probably wanting save/re-sell all the unused parts but can you drill holes into the hub and then split it with a chisel?

[Threedj16]

Those splines look rusty; perhaps a soaking with PB Blaster or the like might help? I know you're probably wanting save/re-sell all the unused parts but can you drill holes into the hub and then split it with a chisel?

I have it soaking in some Kroil oil right now....LOL. But I don't want to bust it as I am actually using that pulley for the drive. Though if I can find spline drives, I might convert both over to timing pulleys. Would make things easier with a double pulley on the spindle. I run timing pulleys and belts on my mill now. Just the spline part is throwing me for a loop.

Any suggestions on the relay deal? There are only two left in stock on Amazon...LOL....chomping at the bit to make one of them mine if folks here thing it is a good idea.

[Threedj16]

Well, they were down to one relay board left....LOL. Had to pull the trigger and grab it. At least using a relay board, it gives more flexibility to change up NO to NC and such. Keeps my 5v positive and 24v positive segregated and seems like a simple solution.

Anyway, still would appreciate any feedback on the relay board, whether it was a dumb idea or not. Also if anyone has removed that spline pulley without busting it....LOL...I'd sort of like to save it whether I use it or not. Haven't had much luck locating spline shaft timing pulleys except from a couple of places that don't really sell online. Custom sounds expensive...LOL.

[Threedj16]

Typical Amazon, they ended up not have the one board left in stock. But that turned out better for me anyway. Watched Marty's video again and realized he used the 24v supply for the alarm circuit, then looked at the manual specs which also state it will allow 24v on the alarm circuit. So now I just need the two block relay anyway for the tool turret. So worked out anyway.

Well, I've tried here and the Emco Yahoo groups for info on pulling the spline drive spindle pulley and haven't heard from anyone who's actually done it. So guess I'll try and block up the back of the pulley somehow and use a gear puller on it this weekend. Going to attempt to replace the pulley with a double timing pulley and swap out my motor pulley to a timing pulley. That will make it much easier to setup my encoder on a pulley also.

I am starting to worry now about how much stuff is now going to be mounting on DIN rails for this setup...LOL. Gone a little crazy with DIN rail components. But I did built a support system for mounting two rails easily, three in a pinch (but with three, no room for wire ways, which I really prefer).

Maybe some pics this weekend if I can get some stuff done.

[spindle Nerd]

Drill and tap two holes across from each other 3/8 and use a bar puller , make a plug to go into end of spindle shaft with a center drilled in it ,for the puller screw.

If you soaked it it should come off without to much trouble, you can buy split clamp style timing belt pulleys just slip over the splines and clamp them down, and Bob's your uncle you have pulleys.

[Threedj16]

Drill and tap two holes across from each other 3/8 and use a bar puller , make a plug to go into end of spindle shaft with a center drilled in it ,for the puller screw.

If you soaked it it should come off without to much trouble, you can buy split clamp style timing belt pulleys just slip over the splines and clamp them down, and Bob's your uncle you have pulleys.

Thanks. I've looked around at a lot of timing pulleys and haven't seen any split clamp. Do you happen to have a link? I also saw in another post here somewhere a discussion on pulley sleeves of some sort from McMaster-Carr. Wonder if that would work?

For temporary purposes, I may just 3D print a helical gear to replace the encoder plate behind the spindle pulley and couple it with a matching gear on the new encoder. At least this is something i could get up and running quicker. Either way, I have to get that pulley off first....LOL. I saw another group member did something similar with spur gears. Though I think helical gears would give a better mesh and run more quiet (even if it temporary).

[spindle Nerd]

Thanks. I've looked around at a lot of timing pulleys and haven't seen any split clamp. Do you happen to have a link?


http://www.sdp-si.com/products/Timing-B ... index.php

[Threedj16]

Interesting development today. I managed to get the original pulley off and come to find out, it is plastic (it rang like metal due to the metal encoder wheel bolted to the back). Anyway, only a small recessed portion at the back end of the pulley (away from spindle bearings) has the splines. So the actual spindle shaft is a smooth 25mm (which is a greater diameter than the splines too). So looks like it will be easy just to buy some standard set screw timing pulleys for my setup. Not having to do anything custom will be much cheaper. My motor is a 15mm shaft. I'll setup a two to one ration on the motor to spindle (as I have a 6500 RPM motor). I think this will end up working out nicely.

But I do appreciate the link. This is my standard place to buy timing pulleys and belts....very reasonable and web store. https://www.bbman.com/belt-length-calculator/